SK130296A3 - Device and method for sealed electronic packaging for environmental protection of active electronics - Google Patents

Abstract

An environmentally sealed electronics assembly. The assembly includes a flexible envelope surrounding the active electronics board. The electronics board is insertable into the envelope and with subsequent sealing provides a reenterable but environmentally sealed active electronics package. Methods of manufacturing the assembly are also described.

Description

Device for sealed packaging of active electronics components for protection against environmental influences and method of sealed packaging of active electronics components

Technical field

The present invention relates to the protection of active electronic components from environmental influences. Specifically, the present invention relates to an apparatus for the use of packaged printed circuit boards of active electronics and similar assemblies intended to protect it from environmental influences. In particular, the present invention relates to a package that allows access to active electronic printed circuit boards for repair and reconstruction purposes.

The prior art backed up by central

Traditionally, many elec- tronics elements were in telephone networks located in central offices, or in smaller smaller rooms designed exclusively for electronic devices that were located outside the central office. This remote electronics is usually powered by electricity from the central grid and is a battery backup office operating environment where temperature and humidity are very precisely controlled to ensure proper operation. Electronics element. The electronics in such an outdoor location outside this central room were usually located in specially built rooms with controlled environmental parameters, or at least the electronics were placed in rooms where it was possible to maintain the temperature above the outdoor environment by using a large amount of heat. he issued an electronic system of himself.

Recent advances in digital signal processing have made it possible to produce new and more capable portable systems. Many of these new systems have created the need to locate active electronics components outside a central room, in a normal outdoor environment, where components are exposed to large changes in temperature, humidity, and are also exposed to all environmental pollutants. In order to gain the full benefit of these new portable systems, it is necessary to place this electronics in very small units that are fed from central nodes by means of transmission media. These units themselves generate very little heat and are therefore very sensitive to moisture damage, as was the case with components used in the past, because their inadequate heat generation does not allow them to keep them dry. As a result, there has been an increase in the requirements for protecting these active electronic components from environmental exposure.

A typical small electronic unit placed in a telephone network will be installed technically with the help of simple tools and limited supervision only. The service life of this electronic unit is expected to be around 20 years. Because these units will be relatively expensive, it is equally important that they are repairable during manufacture and even after being recovered from the site. These systems will soon require a full range of component types to be able to exhibit the high cost / cost ratio required by new telephone network architects.

Electronic components adapted to be more resistant to environmental influences already exist for use in military applications and the automotive industry. Military equipment relies on the use of specially selected and carefully installed components, which are then deployed in expensive sealed packages. The gaskets of these packages are maintained by personnel who follow precisely specified maintenance procedures to maintain these components, and their service life is, in addition, relatively short. The materials used in these applications are mostly metals and ceramics that are resistant to the absorption of moisture and contaminants. However, such hermetically packaged electronic systems are very expensive for ordinary use for commercial purposes. The automotive industry relies in this area on the use of specially selected components that are sealed using polymer plastic casting technology. However, this excludes the possibility of repairing these components and the possible return of components to service. Since these sealed modules contain relatively small and inexpensive electronic systems that are unlikely to ever require some repair, these encapsulated polymers suitable for this application can be used.

However, these conventional solutions are inadequate for new telecommunications systems because they rely on limited sets of components, well trained and supervised maintenance personnel and a warm environment and on the possibility of throwing away these components instead of replacing them.

Among industrial applications and the use of active electronics such as microprocessor assemblies, dynamic random access memories (DRAMs), but also other components such as resistors, encoders, transformers, printed circuit breakers, electro-optical devices and the like, these are often subject to static electricity and other types of hazardous effects against which electronic components need to be protected. This is generally achieved by sealing the components in conductive plastic tubes or in transparent or semi-transparent plastic or nickel-plated plastic bags. However, it has not yet been acknowledged that such electronic components, i. In-use electronic devices in operation when generating heat can be effectively sealed without possible overheating in the system to protect them from environmental influences and allowing subsequent access to printed circuit boards or other electronic devices to repair components; and reuse of printed circuit boards or other electronic devices. This unexpected knowledge or discovery made by the inventor is a particular factor in the present invention.

The sealing of multi-pin electronic connectors with a rubber seal is well known. Connectors sealed in this way will operate where the connection made by them is exposed to accidental soaking in water or in situations where heat-drying heat is accessible or where the connection is exposed to a frequent maintenance program. However, in situations where components are exposed to environmental influences for a long time without drying heat, the connectors become internally damp due to the transfer of evaporated water through the insulating polymer material. This moisture will cause water leakage and corrosion at the same time, which will cause component failure. The use of a barrier system, combined with the selected plastic seal, is uniquely effective in blocking these leakage paths without adversely affecting the mechanical bending of the contacts or surface contacts. Exceptionally, this combination effectively prevents short circuits even if the connector has been connected or disconnected multiple times.

SUMMARY OF THE INVENTION

The present invention relates to a sealed package of active electronics components intended to protect it from environmental influences by means of a protective flexible packaging material, including a moisture barrier, which is combined with a connector sealing system that protects the electronics also during operation when it occurs generation of heat by electronic elements, without any overheating of the electronics. The sealing system has no effect on the process of the electronic assembly and can be removed and repositioned many times without damaging the electronics, whilst allowing complete repair of the electronic components. The invention also provides a method of manufacturing sealing subassemblies into which active electronic elements can be inserted, which simplifies the final sealing of the active electronics. The use of plastics for sealing and packaging materials produces a non-hermetic coating, potentially hazardous effects of moisture and other hazardous chemicals that can diffuse through the plastic material can be absorbed by optionally including a small amount of desiccant / absorbent inside the packaging. Thus, the invention provides many other advantages beyond those described above, which are obvious to one of ordinary skill in the art to which the foregoing description relates.

Overview of the drawings

Fig. 1 shows a bag sealed against environmental influences, with sealed pins and sockets of a multi-pin connector, into which the active electronics element can be inserted and subsequently sealed therein.

Fig. 2 shows a cross-section of one embodiment of a sealed package for electronics of a laminate construction.

Fig. 3 shows a cross-sectional view of the pins and sockets of a connector with a conventional seal.

Fig. 4 shows a cross-section of pins and sockets of a connector in an embodiment when the seal is made using an elastic sealant combined with a barrier structure.

Fig. 4b shows a cross-section through the connected pin and socket connector of FIG. 4, the moisture leakage path is also blocked here.

Fig. 5a shows a cross-section of sealed pins and sockets of one embodiment of a connector adapter based on a conventional DIN wire connector.

Fig. 5b shows a cross-section of sealed pins and sockets of one embodiment of a connector adapter based on a conventional DIN wire connector.

Fig. 6 illustrates a cross-section of sealed pins and sockets of one embodiment of a connector adapter that is based on a connector of conventional construction.

Fig. 7 illustrates a cross-section of a sealed edge connector of a printed circuit that uses a seal barrier construction on the connector.

Fig. 8 shows a view of an embodiment of a guide and latch system by which a printed circuit board is fastened to an adapter without the need for direct access when fastening components.

Fig. 9 illustrates an embodiment mechanically protecting the seal of the electronics package.

Fig. 10 illustrates a plurality of sealed active electronics modules assembled into a plurality of boards connected by a sealed cable.

Fig. 11 illustrates a sealed active electronics module using a structure that is more resistant to impact and crease.

Fig. 12 shows an embodiment for obtaining more thermal energy from a sealed package of an electronic element.

Fig. 13a illustrates the portion shown in FIG. 12 after it has been assembled and the cross-section of the path dissipating the thermal elergy.

Fig. 13b illustrates the portion shown in FIG. 12 after it has been assembled and the cross-section of the road dissipating thermal energy.

Fig. 13c shows an alternative embodiment of a thermal energy dissipation structure.

Fig. 14a illustrates an embodiment of a sealed active electronics module in which a sealed cable is used for interconnection, instead of a sealed multi-pin connector.

Fig. 14b shows an embodiment of a sealed active electronics module in which a sealed cable is used for interconnection, instead of a sealed multi-pin connector.

Fig. 15 shows an embodiment of a sealed bag for insertion of an electronic element followed by a seal using an edge type connector.

Fig. 16 illustrates an alternative packaging embodiment wherein an electronic element is inserted into a protective bag and an edge type connector is used herein.

Fig. 16a illustrates an alternative packaging embodiment wherein the electronic element is inserted into the protective bag and an edge type connector is used herein.

Fig. 16b illustrates an alternative packaging embodiment wherein the electronic element is inserted into the protective bag and an edge type connector is used herein.

Fig. 17 illustrates another alternative embodiment of a protective wrapper using a ring-type adapter and two canvas closure pieces.

Fig. 18 illustrates an improved packaging system for use in underground applications, or if the electronics may be submerged under water for a long period of time.

Examples of the invention

A particularly preferred embodiment of the invention will be explained more fully by the accompanying drawings. More specifically, FIG. 1 shows a sealed electronic element wrapper 100 having a shape that is capable of inserting the entire printed circuit with the active electronics elements 1000. Of course, the sealed electronic element wrapper may have any suitable shape that will allow insertion of the desired printed circuit. The wrapper can be made of separate layers joined together, or a single layer of material that will be folded as shown in the figure. More specifically, the sealed electronics package 100 is comprised of a layer of material 10 capable of providing environmental protection (moisture) that is formed into a tube of a size suitable for inserting a printed circuit with active electronic elements 1000.

The tube can be made with a seam or a seam. The layer of material 10 is sealed either by adhesive or by welding along the longitudinal seam 12 and around the adapter module 18 with a pin connector 16 extending through and extending in and out of the adapter module.

An airtight seal is constructed around the contact of the pin connector 16 which passes through the adapter 1.8 in the manner described below. The pin connector contacts 16 extending inwardly of the housing 100 are capable of being coupled to the connector 19 on the electronic press connection 23 and the pin connector contacts 16 extending out of the housing 100 are capable of being coupled to the sealed connector 20 which transmits the signal from the active electronics 1000 to the rest of the system. . The stabilizing blocks 25 are secured to the active electronics 1000 so as to prevent damage to the own electronics. This feature will be described in more detail below. The active electronics 1000 is inserted into the open end of the drawn package 100 until the connector 19 abuts the connector pins 16 extending inside the package 100. In some cases, the active electronics 1000 will have sharp points, slightly protruding from its surface. These sharp tips could pierce the layers of material 10 and cause leakage through the package. They can be effectively treated by first coating the active electronics elements 1000 with an extruded plastic tube with large openings, plastic foam, paper, or paper that would also contain the non-finished material. Said materials are inexpensive, have no adverse effect on heat transfer, and are strong and strong enough to prevent sharp spikes from piercing the material layer 10. After the connector 19 is wrapped with a protective, an absorbent material package (desiccant) is attached thereto. 22 which is thus inserted into the open end of the package 100 and the trailing edge 14 is sealed using a simple package sealing machine, on a thermal principle.

Alternatively, this seal may be made using a gel sealer and a metal clamp, or a Velcro or normal zipper. These types of seals have the advantage that they can be easily opened and re-closed. Once this seal is complete, the active electronics 1000 is protected from the effects of moisture and other contaminants. In some cases, it is necessary for the end user of the electronic assembly to be able to view the control lights that are on the edge of the active electronics element 1000. The transparent window 21 is located in the layer of material 10. through which these warning lights can be viewed. Preferably, the window will be moisture, for example plastic

Optionally, a non-return valve may be placed in the package to allow overpressure leakage if the package has been sealed at normal sea level pressure, and the system is then used where the pressure is constantly lower, for example at high altitude, or preferably small volume The air can be introduced into the package after its final sealing, so that in case of any changes in temperature or pressure during operation, the volume of the flexible laminate will be generated without generating an internal overpressure.

A suitable range of operating temperatures is -40 ° C to 93 ° C (-40 ° F to 200 ° F). The pressure will vary from a sea level pressure of 101, 325 kPa to a pressure of 6080 m, or about 43,165 kPa.

The layers of material 10 and a particularly preferred embodiment are described in FIG. 2 and generally has to withstand an impenetrable approach with an ITO coating.

the electronic barrier element can change moisture, must resist piercing with any sharp spikes, and must maintain continuity throughout the product's service life. Any lgimited or substrate material capable of withstanding puncture, chemically aggressive environments and temperature extremes while maintaining a high level of protection against the passage of moisture and protection against other environmental hazards is suitable for use with the present invention. In particular, materials which are known to be stable and cohesive for a long time under these operating conditions are suitable for use.

The preferred embodiment of the laminated structure would be of sufficient thickness to allow handling of the electronic element without the possibility of piercing the package, tearing it, or losing the integrity of the weld. Ranges for layer thickness are up to 0.3 millimeters for outer shell layers, 0.1 mm for inner shell layers and 0.0254 mm for middle shell layers. Said layer of material 10 consists of an upper and a lower layer of a suitable material, such as high density polyethylene having a thickness of less than 0.15 mm, and inner layers which are of an ionomer about 0.05 mm thick, and finally a middle layer, which is about 0.0254 mm thick and is made of metal, such as aluminum, or other suitable material. Interlaminar strength of the connection should remain above the 35 kgm ^- · ^ = 350 Nm "l (i.e., 2 lbs.inch ^- ^), according to ASTM D 1876-93. Optionally, the inner surface of the material may be black to absorb heat radiated by active electronic elements during operation. In addition, both exterior and interior surfaces can be made with an antistatic coating to reduce electrostatic discharge potential (ESD). In certain environments, the wrapper is an inner and outer plastic layer with a middle metal layer. Usable thicknesses are 0.38 mm, 0.0254 mm and 0.38 mm.

The general properties of the material layer must be as follows (the materials must satisfy them): the puncture resistance when tested with ASTM F 1306-90 with a screwdriver end must be greater than 11.35 kg, and with a needle end, this resistance should be greater than 6.81 kg. Preferably, the screwdriver puncture resistance should be greater than 13.62 kg and the needle puncture resistance greater than 9.08 kg. The material should have a tear resistance greater than 3.623 kg, preferably greater than 5.448 kg when tested according to ASTM D 2582-93. The heat weld obtained on the seam of the laminate when shaped into the bag should resist separation by a force of more than 13.62 kg, but preferably a force of more than 15.89 kg when the material is tested according to ASTM D 1876-93. These performance characteristics should not decrease significantly with time passage or environmental exposure.

A suitable laminate is redrawn in Patent Application WO 92-19034, (US No.:08/129201, filed Sep. 13, 1993), which is fully incorporated herein by reference, but also any laminate layer capable of puncture resistance and at the same time preventing moisture penetration and protecting the electronics from environmental hazards such as pollution is suitable for use with the present invention. Fig. 2 illustrates a preferred embodiment of a laminated structure.

The layer thickness ranges may be between 75 and 350 microns (microns) in the layers 10a and 10e, between 20 and 200 microns for the layers 10b and 10d, and between about 5 and 75 microns for the layer 10c.

The material of the layer 10 consists of an upper layer 10a and a lower layer 10e, which are made of a suitable material, such as low density polyethylene and about 200 microns thick, and further comprising two inner layers of about 80 microns thick, is a cast polyamide or polyester, and finally there is a middle layer, about 20 microns thick, made of aluminum or other suitable material. Alternatively, however, this is not shown in the figure, the inner surface of the material may be provided with a black color or other heat-absorbing material emitted by the active electronics during its operation. Inside is meant that part of the layer of material that, after welding the material into an envelope or a sealed package, will have clear sides that will be facing the opposite sides of the printed joint.

In some cases, it is desirable for the laminate to have a three-dimensional shape instead of being flat. This can be achieved by forming a layer of material before welding. If a large package volume is required, the aluminum layer may be replaced by a layer of other highly plastic material, such as tin, tin alloys and the like, which are capable of withstanding large deformations. The material used to manufacture the window 21 must also, and best of all, block the ingress of moisture inside the package, also the penetration of chemical contaminants and electronic noise, while still remaining transparent. This can be achieved by using a transparent plastic coated with a thin coating of inorganic material such as indium tin oxide (ITO), silica SiO 2, alloyed titanium dioxide TiO 2, alloyed aluminum oxide Al 2 O 3, and the like. For example, a multilayer laminate made of low density polyester and polyethylene can be used with or without inorganic coatings.

The material layer 10 may be cast with the adapter 18 if the inner layer of the flexible laminate and the adapter are made of a similar polymeric material. Casting is the preferred embodiment. For example, the adapter may be made of polyethylene or a suitable thermoplastic, which are both conventional for packaging and injection molding, and the production of an inner layer of material may be made of the same material by bringing sufficient heat to the point where the materials join. In addition, if the outer material layer corresponds to the adapter material, it will be possible for the outer layer to flow and associate with the adapter material and cover the thick edge of the material layer.

Alternatively, the edges may be adhesively sealed to form a closure. In a preferred embodiment of the invention, the layer of material 10 is sealed and secured to the adapter 18 by means of hot melt adhesive or reaction hot melt adhesive. Specifically, it is a hot melt adhesive based on styrene-butadiene-styrene, SBS polyamide or polyester, or a thermosetting epoxy adhesive, polyurethane or polyester can also be used. It is important that the high-frequency sounds be unlocked and do not pass through the package 100, which is achieved by the active electronics 1000 being enclosed in a hydrogen layer. The film layer in the material 10 may be effective for this purpose, and the conductive internal surfaces of the adapter 1.8, such as evaporative dyeing with a conductive varnish, to avoid the layer may be applied to various processes, deposition, cladding, or

Care should be taken to shorten the connector pin 16. The electrically conductive hot plug may be used to bond the film layer in the material layer 10 to the conductive layer on the inner surface of the adapter 18.

For this purpose it is with a dryer that would melt the adhesive.

Electrically conductive adhesives melting at high temperatures can be formed by adding conductive fillers to the known high melting temperature adhesive. The description of such materials as well as alternative ferromagnetic cartridges could be such that the portable magnetic fields will provide heating during the assembly. U.S. Pat. No. 08/049900 describes just such materials. The app is fully included in a range of different links.

Also with these measures a small amount of moisture (about 30 micrograms / hour) and contaminants such as hydrogen sulphide H ₂ S, sulfur dioxide SO ₂ , chlorine Cl ₂ , and nitrogen dioxide NO ₂ will be transferred through the polymer seal of the package 100 and damage active electronics 1000th

inside the package 100 an inserted bag should solve the problem of moisture transfer. The bag absorbs this small amount of moisture and contamination long after 20 years of system life. In a preferred embodiment of the invention, silica gel, alumina, or molecular mesh is used to absorb moisture and contamination. Naturally, it is important that the bag of the dryer 22 is kept dry, unreacted, until the package 100 is sealed (closed). Suitable examples are described in U.S. Patent Application Ser. No. 07/973922, filed Nov. 22, 1992, which is hereby incorporated by reference in its entirety. It is also important that the dryer package 22 is never accidentally left unpacked 100 during final assembly. The package 22 is anchored inside the package 100 such that a clear view through the window 21 in the package is maintained.

In a preferred embodiment of the invention, the desiccant is sealed in a polyethylene bag whose moisture permeability is so high that the pouch can maintain low moisture inside the active electronics package, but still low enough to protect its own desiccant bag from moisture before it is put into the active electronics package. Alternatively, the desiccant is sealed in a non-leaking container having, on one side, punctured holes. These openings are sealed with an adhesive patch that is attached to a long color tape. Using a pressure-sensitive adhesive, the package is held at a known location within the package 100 by a tape that extends out of the open hole and has its free end attached to the outside of the package 100. Before finally sealing the back 14 of the package, pull out the tape to expose the dryer for a short time to the outside of the dryer before the active electronics package is finally closed. After this final closure of the package 100, the integrity of the seal can be tested by heating the sealed package of active electronics elements in the oven for a few minutes or hours. The heat will cause the air in the package 100 to expand and leak, or visibly expand the properly sealed blister 100. When the package is cooled to room temperature, if it leaks, it will instantly collapse and be easily detectable. Alternatively, before a final seal is made, a pressure test may be performed by inserting a rubber plug into the open end of the package 100 and connecting the package to a source of pressurized air through said plug and immersing the package under water.

Pressurizing the package will result in leakage of bubbles from the package, which is easily visible. Another alternative test is the vacuum or compression test, which can also be used for the same purposes.

Effective sealing of the active electronics elements 1000 also requires sealing of the pin connector 16 when it is inserted into the connector 20. when both are to provide a completely sealed system. Fig. 3 shows a cross-sectional view of a usually achievable sealed connector. It consists of a male counterpart (plug) 1900, a gasket 1901. connector pins 1902, a female counterpart (plug) 1903. and a pin receptacle 1904. When the plug 1900 fits into a socket 1903. the gasket 1901 is pressed firmly between the top of the connector 1910 and seal. According to the present invention, if the back of the connector 1911 as well as the back of the connector 1912 are sealed with potting material or in the package 100. water cannot leak into the cavities around the connector beds 1904. This type of connector construction will prevent the formation of conductive paths in the connector for a short time. but since moisture and contamination can be transmitted through the molded plastic polymer, retaining the pins when constantly exposed to high moisture and contamination, the cavities around the connector beds 1904 will eventually become wet and contaminated. This contamination will provide moisture leakage paths between the connector beds 1904 and will also corrode the connector beds 1904 as well as the pins 1902. This will reduce the quality of the connection made.

Fig. 4 and FIG. 4b show a partial cross-section of a connector according to a preferred embodiment of the invention which provides a much better sealing of the connector. Plug 2000 is identical to conventional plug 1900, but the design of socket 2003 is different from socket 1903. Socket 2003 is made by inserting the connector beds 2004 into the polymer top polymer cover 2015 is the bed 2004. The top polymer with crossbars 2013. which plate base 2016. Then installed over The connector cover 2015 is made to surround each connector bed 2004 up to the base plate 2016. Hydrophobic is, for example, lubricating grease, or preferably is, and extends beyond a seal, such as an elastic gel, completely filled into drawer 2003 so as to nearly cavity in drawer 2003. as described

Claims (1)

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